changed parameters form `kernel_pid_t` to `int`
dist/tools: add cppcheck script

enables easy linting of the whole tree or just one branches changes against
another
board/pca1000x: added/fixed dist scripts

- pca10000: added author to debug.sh
- pca10005: added debug and reset scripts
- pca10005: fixed flash script
- pca10005: adjusted env vars in Makefile.include
Fix thread_yield by avoiding the (too) early re-enablement of IRQ,
that is: before the newly selected thread's context is totally restored
Prevent the compiler to add an unwanted prologue in thread_yield()
Fix the race condition when an interruption occured at the beginning
of thread_yield(), i.e.: just after SR(R2) was pushed but before
the rest of the suspended thread's context was pushed!
tests: improve calculation in hwtimer_wait

Kudos to @Kijewski
SQUASHME: file(line) -> file:line

Addresses https://github.com/RIOT-OS/RIOT/pull/1604#discussion_r16936195
iot-lab_M3: extend debug target for iot-lab_M3
SQUASHME: kill openocd by PID
cpu/stm32f1: spi_transfer_bytes proper counting.

The transferred bytes were being counted more than once because of a +=
when calling spi_transfer_byte().

This patch should also handle errors from spi_transfer_byte() better
since it is now possible to detect errors _after_ the first byte has
been successfully sent.

Signed-off-by: Joakim Gebart <joakim@gebart.se>
cpu/stm32f1: Reduce scope of ret variable in spi_transfer_bytes.

Reduced scope to inside the while loop as per comments in RIOT-OS/RIOT#1630

Signed-off-by: Joakim Gebart <joakim@gebart.se>
Merge pull request #1630 from gebart/stm32f1-spi-fix

cpu/stm32f1: spi_transfer_bytes proper counting.
sys: vtimer: add license header
Merge pull request #1634 from kaspar030/vtimer-license

sys: vtimer: add license header
Merge pull request #1628 from LudwigOrtmann/hwtimer_wait_fixup_2

tests: improve calculation in hwtimer_wait
native: add support for Linux on ARM
Merge pull request #1627 from LudwigOrtmann/native-arm

native: add support for ARM (Linux)
Merge pull request #1629 from thomaseichinger/iot-lab_debugger++

iot-lab_M3: extend debug target for iot-lab_M3
core: priority_queue: simplify inheritance